#define DATA 3
#define LATCH 4
#define CLOCK 5

uint8_t cislo = 0;
unsigned long previousMillis = 0;

const uint8_t cislice[] = {
  0b00000011, // 0
  0b10011111, // 1
  0b00100101, // 2
  0b00001011, // 3
  0b10011001, // 4
  0b01001001, // 5
  0b01000001, // 6
  0b00011111, // 7
  0b00000001, // 8
  0b00001001, // 9
  0b11111111, // --
};
uint8_t segment[] = {1, 2, 4, 8};

void setup() {
  pinMode(DATA, OUTPUT);
  pinMode(LATCH, OUTPUT);
  pinMode(CLOCK, OUTPUT);
}


void loop() {
  zobraz(cislo);
  if (millis() - previousMillis >= 1000) {
    previousMillis = millis();
    cislo = (cislo + 1) % 10000;
  }
}


void zobraz(uint8_t cislo) {
  for (int i = 0; i < 4; i++) {
    uint8_t cifra = cislo % 10;
    cislo = cislo / 10;

    digitalWrite(LATCH, LOW);
    shiftOut(DATA, CLOCK, LSBFIRST, cislice[cifra]);
    shiftOut(DATA, CLOCK, LSBFIRST, segment[i]);
    digitalWrite(LATCH, HIGH);
  }
  delay(200);
}